This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2000-186446, filed Jun. 21, 2000, the entire contents of which are incorporated herein by reference.
The present invention relates to a microwave module for use in, for example, a telecommunication apparatus or a radar apparatus, etc.
In general, a microwave module of this type has a shield structure as shown in FIG. 1, which comprises a metal case 1, and a circuit board 2 thermally connected thereto and received therein. The circuit board 2 has a high-frequency transmission circuit, a high-frequency reception circuit and a DC circuit, such as a power supply or an oscillation circuit, mounted thereon. The metal case 1 has a transmission-side waveguide connection port 3 and a reception-side waveguide connection port 4 formed therein. The transmission-side connection port 3 and the reception-side connection port 4 are connected to the connection terminals of the high-frequency transmission circuit and the high-frequency reception circuit on the circuit board 2 in the metal case 1, respectively, via their respective waveguide conversion members (not shown) called xe2x80x9cwaveguide conversion probesxe2x80x9d.
Further, the transmission-side connection port 3 and the reception-side connection port 4 of the metal case 1 are connected to a transmission-side connection port 6 and a reception-side connection port 7 incorporated in a waveguide-type diplexer 5 for separating a high-frequency transmission signal and a high-frequency reception signal on the basis of their frequencies. The diplexer 5 also has an antenna connection port 8 to be connected to an antenna connection port (not shown) for signal transmission and reception, thereby constituting a desired telecommunication system.
In the above microwave module, however, the waveguide-type diplexer 5 attached to the metal case inevitably projects therefrom, since the transmission-side connection port 6 and the reception-side connection port 7 of the diplexer 5 must be respectively connected to the transmission-side connection port 3 and the reception-side connection port 4 of the metal case 1. This means that the module is large in size and hence requires a large installation space.
The problem of how to reduce the required installation space of the module is one of important problems that must be solved to satisfy the recent demand to downsize telecommunication devices and radar devices.
It is the object of the invention to provide a compact microwave module of a simple structure capable of accurately separating high-frequency signals on the basis of their frequencies.
To attain the object, there is provided a microwave module comprising: a diplexer made of a conductive material, having a waveguide formed therein for separating a high-frequency transmission signal and a high-frequency reception signal on the basis of their frequencies, and having a transmission-side connection port, a reception-side connection port and an antenna connection port formed in peripheral portions of the diplexer such that the ports communicate with the waveguide; and a circuit section thermally connected to one side of the diplexer and grounded via the diplexer, the circuit section including a high-frequency transmission circuit connected to the transmission-side connection port, a high-frequency reception circuit connected to the reception-side connection port, and a direct-current circuit.
In the above structure, the diplexer executes its intrinsic function of separating, on the basis of frequency, a high-frequency transmission signal to be transmitted to the high-frequency transmission circuit of the circuit section provided on the one side of the diplexer, and a high-frequency reception signal received via the high-frequency reception circuit of the circuit section. The diplexer also functions as a base plate for earthing the circuit section and for executing its thermal control.
Since, thus, the diplexer has both the earthing function and the thermal control function, the module can be made by a smaller number of component parts. Further, the module has a stacked structure in which the circuit section is mounted on one side of the diplexer. By virtue of this structure, the module can be made compact.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.